This invention relates to a reinforcing bar coupling apparatus that can carry tension that is applied to reinforcing bars by mechanically coupling the opposed ends of the reinforcing bars without coupling the reinforcing bars by overlapping them while the reinforcing bars are used in reinforced concrete construction. The opposed ends of the reinforcing bars are enabled to be coupled by contacting with members securing the opposed ends of the reinforcing bars and instantly applying strong external forces by hydraulic pressure to the members.
Referring to a related art reinforcing bar coupling apparatus (see FIG. 12), the related art coupling apparatus is provided with a pair of coupling members 12, whose inner surface has a plurality of joint grooves 12b and opposite ends of an outer surface have respective male threads 12a. The related art coupling apparatus includes sleeve couplings 11 that have a through-hole 11b in the center of each of the sleeve couplings and female threads 11a on an inner surface of the through-hole 11b so that the sleeve couplings 11 can be screwed to the externally threaded opposite ends of the outer surfaces of the coupling members 12. The reinforcing bar coupling apparatus 10 is structured in the manner that after two reinforcing bars 1 having multiple joint protrusions 1a are linearly arranged to be in contact with each other at opposed ends thereof, the pair of coupling members 12 are combined with the reinforcing bars 1 so that the joint protrusions 1a of the reinforcing bars 1 fit into the joint grooves 12b by locating the junction of the two reinforcing bars 1 in the midpoint of the inside of the coupling members 12. Thereafter, the sleeve couplings 11 having the through-holes 11b are fitted over the reinforcing bars 1, and the sleeve couplings 11 are screwed to the male threads 12a and manually tightened to be combined with the male threads 12a. Accordingly, the reinforcing bars 1 are integrally combined with the pair of coupling members 12, so that the reinforcing bars 1 are coupled together. However, the reinforcing bar coupling apparatus 10 of the related art is problematic in that when the opposed ends of the reinforcing bars 1 to be coupled are not accurately cut, the opposed ends of the reinforcing bars 1 may not be in close contact with each other inside the reinforcing bar coupling apparatus 10. Accordingly, the reinforcing bars 1 may sway inside of the reinforcing bar coupling apparatus 10. In addition, to couple two reinforcing bars 1 using the coupling apparatus 10 of the related art, the two coupling members are arranged to face each other and compressed by the combination of the sleeve couplings. However, when coupling the two reinforcing bars, the coupling members may not apply enough compressive force to the reinforcing bars. This problem causes the coupled reinforcing bars inside the reinforcing bar coupling apparatus to be loosened, or to move, so that the compressive or bending strength of the coupled reinforcing bars is weakened at the coupled junction, and thus a reinforced concrete structure has decreased rigidity to compression or bending.